JP4947452B1 - Method for measuring thread elements at the end of pipes - Google Patents

Abstract

The present invention provides a method for automatically and accurately measuring a thread element of a threaded end of a pipe on-line (threading line).
The present invention is a method for automatically measuring screw elements at the end of a pipe after threading on a threading line 100 in which the end of the pipe P that is sequentially conveyed is threaded. A cleaning step of cleaning the threaded tube end portion with the screw cleaning device 30, a drying step of drying the cleaned tube end portion with the screw drying device 40, and a screw element of the tube end portion after the drying Is measured by the automatic screw element measuring device 50, and at least in the measuring step, the tube end is placed in a clean atmosphere.
[Selection] Figure 1

Description

  The present invention relates to a method for automatically and accurately measuring a screw element at a pipe end portion subjected to screw machining, such as an oil well pipe, on-line.

  Conventionally, oil well pipes and the like have been used by connecting pipe ends to each other using screws machined on the pipe ends. Various improvements in the screw shape and the like have been made with this screw in response to demands for deepening the oil well and corrosive environment (see, for example, Non-Patent Document 1). In some cases, such a screw is formed at the end of a pipe having a length of several tens of meters and a weight of several hundred kg, and has a complicated and highly accurate screw shape. For this screw, a quality control item called a screw element is defined, and it is inspected whether or not the measured value of the screw element is within a predetermined tolerance. Examples of the screw element can include a screw portion outer diameter, a seal portion outer diameter, a parallel portion outer diameter, a screw groove diameter, a screw thread height, a screw groove depth, a screw taper, and a seal taper.

Conventionally, screw elements, which are quality control items as described above, have been measured manually on-line (threading line) using a dedicated measuring instrument, but labor saving, human error suppression, measurement speedup and high accuracy From the standpoint of computerization, development of more accurate automatic measurement technology has been attempted.
Specifically, as a technique for automatically measuring the screw element, the parallel light from the light source is irradiated substantially parallel to the screw groove, and the light leaking to the opposite side of the light source with respect to the tube axis is detected. An automatic measuring device that has an optical sensor and measures a screw element based on the detection result of the optical sensor is known (see, for example, Patent Documents 1 and 2).

Masao Ogasawara, “Recent Oil Well Pipe Fittings” and Steel: Nippon Steel Association, May 1, 1993, Vol. 79, no. 5, pp. N352-N355

Japanese Patent No. 3552440 Japanese Unexamined Patent Publication No. 63-212808

However, in order to apply the automatic measuring device for screw elements as described in Patent Documents 1 and 2 on-line (threading line), there has been an environmental problem.
More specifically, when threading a pipe end, the pipe end is generally screwed using a lathe while spraying lubricant (water and rust inhibitor) to the pipe end. Although it cuts, this lubricant may remain at the end of the tube after thread cutting, leading to deterioration in measurement accuracy of the screw element. In addition, when burr is removed after cutting, the lubricant remains in the same way as during thread cutting, and cutting scraps adhering to the end of the pipe due to burr removal may cause deterioration in measurement accuracy of the screw element. .

  For this reason, it is actually difficult to apply the automatic measurement device for screw elements online and perform total measurement. Therefore, conventionally, automatic measurement is performed after the pipe is extracted from the threading line at an appropriate timing and the lubricant and cutting waste are removed in a test room with good environmental conditions.

  The present invention has been made to solve such a problem of the prior art, and provides a method for automatically and accurately measuring a thread element at a threaded end of a pipe on-line (a threading line). The issue is to provide.

In order to solve the above-mentioned problems, the present invention is a method for automatically measuring screw elements at the end of a pipe after threading on a threading line in which the end of the pipe that is sequentially conveyed is threaded. A cleaning process for cleaning the threaded pipe end, a drying process for drying the cleaned pipe end, and a measuring process for measuring the thread element of the dried pipe end, At least in the measurement step, the tube end portion is placed in a measurement chamber filled with clean air in a positive pressure state .

Since the present invention includes a cleaning process for cleaning the pipe end after threading, the lubricant remaining on the pipe end during thread cutting or burr removal, which may cause a deterioration in measurement accuracy of the screw element, or burr It can be expected that the cutting waste adhering to the pipe end portion is cleaned by the removal. For example, an organic solvent is used for cleaning the tube end in the cleaning process.
In addition, since the present invention includes a drying process for drying the cleaned pipe end, the organic solvent that may remain at the pipe end in the cleaning process is dried, and the measurement accuracy of the screw element by the organic solvent is improved. It is possible to prevent deterioration.
Furthermore, since the present invention includes a measurement step of measuring the screw element at the end of the tube placed in the measurement chamber filled with clean air in a positive pressure state, the screw element can be measured with high accuracy. . For example, an optical automatic measuring device as described in Patent Documents 1 and 2 is used for measuring the screw element in the measuring step.
As described above, according to the present invention, since the tube end portion is placed in the measurement chamber filled with clean air in a positive pressure state, particles present in the atmosphere of the screw processing line adhere to the tube end portion. The possibility of deteriorating the measurement accuracy of the screw element is reduced, and the screw element at the pipe end subjected to the screw processing can be automatically and accurately measured online (screw processing line).

Moreover, in order to solve the said subject, this invention automatically measures the screw element of the pipe end part after a screw process on the screw process line by which the thread process is given to the end part of the pipe conveyed sequentially. A method comprising: a washing step for washing a pipe end after threading; a drying step for drying the washed pipe end; and a measuring step for measuring a screw element at the dried pipe end. wherein, during the period from at least the drying step to said measuring step, the tube end after the threading is provided as a screw element measuring method tube end, characterized in that it is placed under a clean atmosphere.

When the lubricant remaining on the pipe end in the cleaning process and the cutting waste adhering to the pipe end are cleaned and the pipe end is dried in the drying process, the pipe end is exposed to the atmosphere of the threading line. There is a possibility that particles existing in the atmosphere of the screw processing line adhere to the pipe end portion and cause deterioration in measurement accuracy of the screw element.
However, according to the screw element measuring method of the pipe end portion according to the present invention , the pipe end portion is placed in a clean atmosphere at least from the drying step to the measurement step, and therefore exists in the atmosphere of the screw processing line. It is possible to reduce the possibility that particles adhere to the end portion of the tube and cause deterioration in the measurement accuracy of the screw element, and the screw element can be measured with higher accuracy.

Moreover, in order to solve the said subject, this invention automatically measures the screw element of the pipe end part after a screw process on the screw process line by which the thread process is given to the end part of the pipe conveyed sequentially. A method for cleaning a pipe end by spraying granular dry ice together with compressed air to a pipe end after threading, and a measurement process for measuring a screw element at the pipe end after the washing And at least in the measurement step, the pipe end portion is placed in a measurement chamber filled with clean air in a positive pressure state .

Since the present invention also includes a cleaning process for cleaning the pipe end after threading, the lubricant remaining on the pipe end during thread cutting or burr removal, which may cause a deterioration in measurement accuracy of the screw element, or burr It can be expected that the cutting waste adhering to the pipe end portion is cleaned by the removal.
And in the washing | cleaning process of this invention, since granular dry ice is ejected with compressed air and the pipe end part after a screw process is wash | cleaned, the dry ice provided to washing | cleaning will vaporize naturally. For this reason, there exists an advantage that the drying process which dries the pipe | tube edge part wash | cleaned becomes unnecessary.
Furthermore, since the present invention includes a measurement step of measuring the screw element at the end of the tube placed in the measurement chamber filled with clean air in a positive pressure state, the screw element can be measured with high accuracy. . For example, an optical automatic measuring device as described in Patent Documents 1 and 2 is used for measuring the screw element in the measuring step.
As described above, according to the present invention, it is possible to automatically and accurately measure the thread element of the pipe end portion subjected to the thread machining on-line (screw machining line).
Preferably, in the present invention, in the cleaning step, the dry ice is sprayed linearly along the axial direction of the tube while rotating the tube at a rotation speed of 5 rpm to 23 rpm.
If the rotational speed is less than 5 rpm, dry ice will be excessively sprayed on the same location at the end of the tube, and condensation is likely to occur. On the other hand, if the rotational speed exceeds 23 rpm, there is a possibility that the lubricant remaining at the end of the pipe during thread cutting or burr removal or cutting waste adhering to the end of the pipe due to burr removal cannot be sufficiently cleaned.
However, according to the preferable configuration, it is possible to sufficiently clean the end of the tube without causing condensation at the end of the tube.
Preferably, the flank surface of the thread portion of the tube is inclined toward the tube end side from the thread to the thread groove, and is perpendicular to the thread axis direction of the tube. When the angle formed by the center of the spray direction of the dry ice is α, the angle formed by the flank surface on the tube center side from the screw thread is β, and the angle formed by the flank surface on the tube end side from the screw thread is γ In the washing step, the dry ice ejection direction satisfies the condition of β <α <γ.
According to the said preferable structure, it is possible to wash | clean effectively the flank surface of the thread part processed into the edge part of a pipe | tube.

  According to the thread element measuring method of the pipe end part according to the present invention, the thread element of the pipe end part subjected to the threading process can be automatically and accurately measured online (screw machining line). For this reason, it is expected that 100% online measurement is possible.

FIG. 1 is a schematic diagram showing a schematic configuration of a screw machining line for carrying out a thread element measuring method for a pipe end according to a first embodiment of the present invention. FIG. 2 is a schematic view schematically showing an example of the screw cleaning apparatus shown in FIG. FIG. 3 is a schematic diagram schematically illustrating an example of the screw drying apparatus illustrated in FIG. 1. FIG. 4 is a diagram showing the results of a test for evaluating the influence of particles present in the atmosphere of the screw machining line. FIG. 5 is a schematic diagram showing a schematic configuration of a screw machining line for carrying out a screw element measuring method for a pipe end according to a second embodiment of the present invention. FIG. 6 is a schematic diagram schematically illustrating an example of the cleanup maintenance apparatus illustrated in FIG. 5. FIG. 7 is a schematic diagram schematically showing a modification of the cleanliness maintenance apparatus shown in FIG. FIG. 8 is a schematic view schematically showing an example of a screw cleaning device for carrying out the pipe element screw element measuring method according to the third embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings as appropriate.

<First Embodiment>
FIG. 1 is a schematic diagram showing a schematic configuration of a screw machining line for carrying out a thread element measuring method for a pipe end according to a first embodiment of the present invention.
As shown in FIG. 1, in the threading line 100, the end of the pipe P that is sequentially transported is threaded by a predetermined transport device (not shown).
Specifically, first, the pipe P is carried in the pipe axis direction toward the installation position of the thread cutting lathe 10. Then, the end of the pipe P is threaded by the lathe 10 for thread cutting while spraying the lubricant (water and rust preventive agent) to the end of the pipe P. The pipe P, which has finished the thread cutting of the pipe end, is carried out from the thread cutting lathe 10 in the pipe axis direction and is laterally fed to a position facing the installation position of the burr removal apparatus 20.
Next, the burr removal device 20 advances in the tube axis direction toward the end of the tube P. Then, the end portion of the pipe P is removed by the burr removing device 20. As the burr removing device 20, for example, a lathe similar to the thread cutting lathe 10 is used. That is, the burr generated on the screw at the end of the pipe P is removed by the burr removing device 20 while the lubricant (water and rust preventive agent) is sprayed on the end of the pipe P. The burr removal device 20 moves back to the original position after burr removal of the end of the pipe P.

  As described above, the pipe P whose end is threaded is laterally fed to a position facing the installation position of the screw cleaning device 30, and a cleaning process for cleaning the pipe end after threading is executed. The Specifically, the screw cleaning device 30 moves forward in the tube axis direction toward the end of the tube P, and cleaning with an organic solvent is performed.

FIG. 2 is a schematic view schematically showing an example of a screw cleaning device 30 that can be used in the cleaning process of the present embodiment. 2A is a front view partially seen through (the inside of the housing 31 is seen through), and FIG. 2B is a plan view. However, in FIG. 2B, the casing 31 and the nozzle 32 are not shown.
As shown in FIG. 2, the screw cleaning device 30 of the present embodiment includes a casing 31 positioned above the pipe P, a nozzle 32 built in the casing 31, and a position positioned below the pipe P, and the shaft The cleaning brush 33 is rotatable around 33A. The casing 31, the nozzle 32, and the cleaning brush 33 are located immediately above the end of the pipe P on which the nozzle 32 is threaded, and just below the end of the pipe P on which the cleaning brush 33 is threaded. It moves forward in the axial direction of the tube P toward the end of the tube P as a unit until it is positioned. Then, after finishing the forward movement, the organic solvent S as the cleaning liquid is ejected from the nozzle 32. The organic solvent S ejected from the nozzle 32 is sprayed on the end of the pipe P through the opening on the lower surface of the housing 31. At this time, the tube P is rotated in the circumferential direction by the turning roller R, and the cleaning brush 33 is also rotated around the shaft 33A, and the end of the tube P is rubbed with the cleaning brush 33. Through the above operation, the entire circumference of the end of the pipe P is cleaned, and the lubricant remaining on the pipe end during thread cutting and burr removal and the cutting waste adhering to the pipe end due to burr removal are removed. Can be expected.
The screw cleaning device 30 moves back to the original position after cleaning the end of the pipe P.

  Next, as shown in FIG. 1, the pipe P whose end has been cleaned is laterally fed to a position facing the installation position of the screw drying device 40, and a drying process for drying the cleaned pipe end is performed. The Specifically, the screw drying device 40 advances in the tube axis direction toward the end of the tube P, and drying by air is performed.

FIG. 3 is a schematic view schematically showing an example of a screw drying device 40 that can be used in the drying process of the present embodiment. 3A is a front view, and FIG. 3B is a perspective view. However, illustration of the nozzle 42 is abbreviate | omitted in FIG.3 (b).
As shown in FIG. 3, the screw drying device 40 of the present embodiment includes an annular member 41 having an inner diameter larger than the outer diameter of the tube P and a plurality of nozzles 42 attached to the annular member 41. The annular member 41 and the nozzle 42 advance toward the end of the tube P as a unit to a position where they surround the end of the tube P that has been threaded. Then, after finishing the forward movement, air A is ejected from the nozzle 42 toward the end of the pipe P. With the above operation, it can be expected that the organic solvent S that may remain at the end of the pipe P in the above-described cleaning step can be dried.
The screw drying device 40 moves back to the original position after drying the end of the tube P.

  Finally, as shown in FIG. 1, the pipe P whose end is dried is laterally fed to a position opposite to the installation position of the automatic screw element measuring device 50, and the screw element at the pipe end after drying in a clean atmosphere. A measurement step for measuring is performed. Specifically, the end of the pipe P is carried in the pipe axis direction toward the installation position of the automatic screw element measuring device 50 placed in a clean atmosphere. More specifically, the automatic screw element measuring device 50 is installed in a measurement chamber filled with clean air in a positive pressure state, and the end of the pipe P is connected to the measurement chamber from an opening provided in the measurement chamber. And the screw element is measured by the automatic screw element measuring device 50. As the automatic screw element measuring device 50, for example, an optical automatic measuring device as described in Patent Documents 1 and 2 can be used. After the measurement of the screw element, the pipe P is carried out to the outside of the measurement chamber through the opening of the measurement chamber and then laterally fed.

Since the screw element measuring method for the pipe end portion according to the present embodiment described above includes a cleaning process for washing the pipe end portion after screw machining (screw cutting and burr removal), the factor of deterioration in measurement accuracy of the screw element is caused. It can be expected that the lubricant remaining at the end of the pipe during thread cutting or burr removal and the cutting waste adhering to the end of the pipe by burr removal will be washed.
Moreover, since the thread element measuring method of the pipe end part according to the present embodiment includes a drying step of drying the washed pipe end part, the organic solvent S that may remain at the pipe end part in the washing process is dried. Further, it is possible to prevent the measurement accuracy of the screw element from being deteriorated by the organic solvent S.
Furthermore, since the screw element measuring method of the pipe end part according to the present embodiment includes a measuring step of measuring the screw element of the pipe end part placed in a clean atmosphere, the screw element can be measured with high accuracy. It is.

  In the present embodiment, the burr removing device 20, the screw washing device 30 and the screw drying device 40 move forward in the tube axis direction toward the end of the tube P, and burr, wash and dry the end of the tube P. After finishing the above, the mode of retreating to the original position has been described. However, the present invention is not limited to such an embodiment, and the pipe P is carried in the pipe axis direction toward the installation position of each device 20 to 40, and the end portion of the pipe P is burred, washed and dried. After finishing, it is also possible to adopt a mode in which the pipe P is unloaded from the devices 20 to 40 in the pipe axis direction.

Second Embodiment
In 1st Embodiment mentioned above, after the edge part of the pipe P dries in the drying process by the screw drying apparatus 40, until the screw element of the edge part of the pipe P is measured by the measurement process by the automatic screw element measuring apparatus 50. Meanwhile, the end of the pipe P is exposed to the atmosphere of the screw machining line 100. For this reason, before the screw element at the end portion of the pipe P is measured, particles existing in the atmosphere of the screw processing line 100 may adhere to the end portion of the pipe P, leading to deterioration in measurement accuracy of the screw element. There is.

Therefore, the present inventors conducted a test for evaluating the influence of particles present in the atmosphere of the screw machining line 100.
First, the inventors measured the particle density (number of particles per unit volume) with a particle diameter of 0.3 μm, 0.5 μm, and 1 μm for 2 days in the threading line 100 using a particle counter. A commercially available particle counter was used to measure the particle density.
FIG. 4A is a graph showing the average value of the measured particle density within the evaluation time. FIG. 4B is a graph showing the maximum value of the measured particle density within the evaluation time. The present inventors extrapolate the measured values of the particle densities of 0.3 μm, 0.5 μm, and 1 μm shown in FIGS. 4A and 4B (broken lines shown in FIGS. 4A and 4B). Is an extrapolation result), and the particle densities of 5 μm and 10 μm are estimated.

  Next, the present inventors have determined the screw thread from the conveying distance (assumed to be 5 m) of the threaded portion of the pipe P that is transported while being exposed to the atmosphere of the threading line 100, the outer diameter of the threaded portion, and the threaded portion length. The volume of the region through which the section passes during the above-mentioned conveyance was calculated. Then, it was assumed that the particles present in the calculated volume were uniformly attached to the entire threaded portion of the tube P. Specifically, the number of particles having a particle diameter of 1 μm adhering to the entire thread portion of the tube P was calculated by multiplying the particle density having a particle diameter of 1 μm measured as described above and the calculated volume. Further, the number of particles having a particle diameter of 5 μm and 10 μm adhering to the entire thread portion of the tube P was calculated by multiplying the particle density of the particle diameters of 5 μm and 10 μm estimated as described above by the calculated volume. .

  Further, the present inventors assume a case where an optical measuring device including a light source and a light receiving unit is used as the screw element measuring device, and the depth of focus of the light receiving unit is 0.2 mm, and the imaging field of view of the light receiving unit is set. Assuming 5 mm × 5 mm. And among the particles adhering to the whole thread part of the pipe | tube P, the number of the particles adhering to said evaluation area | region (5 mm x 5 mm x 0.2 mm) was computed.

FIG. 4C is a diagram showing the number of particles attached to the evaluation region calculated as described above. FIG. 4C shows the number of particles adhering to the evaluation region in both cases where the outer diameter of the tube P is 178 mm and 60 mm.
As can be seen from FIG. 4C, particles having a particle diameter of 5 μm adhere to the evaluation region of the threaded portion of the tube P with a probability of about 7 to 8% when there are many particles (in other words, 100 tubes Of the P, it adheres to the evaluation region of the threaded portion of the 7 to 8 pipes P). Further, even particles having a particle diameter of 10 μm are attached to the evaluation region of the threaded portion of the tube P with a probability of about 3% when there are many particles. Furthermore, particles having a particle diameter of 1 μm are usually attached to the evaluation region of the threaded portion of the tube P with a probability of about 15%, and with a probability of about 70% when there are many particles.
If the required measurement accuracy of the screw element is about 5 μm and the total number of tubes P is to be measured with high accuracy, the influence of the particles as described above cannot be ignored.

  For this reason, at least from the drying step (step of drying the cleaned tube end) to the measurement step (step of measuring the screw element at the tube end), the threaded tube end is in a clean atmosphere. It is desirable to leave. This point is taken into consideration in the second embodiment of the present invention.

Hereinafter, the second embodiment of the present invention will be described mainly with respect to differences from the first embodiment described above, and the description of the same points as the first embodiment will be omitted as appropriate.
FIG. 5 is a schematic diagram showing a schematic configuration of a screw machining line for carrying out a screw element measuring method for a pipe end according to a second embodiment of the present invention.
As shown in FIG. 5, also in the threading line 100A of the present embodiment, the end of the pipe P that is sequentially transported is subjected to threading (screw cutting and burr removal) by a predetermined transport device (not shown). The As in the first embodiment, a thread cutting lathe 10 is used for thread cutting, and a burr removing device 20 is used for burr cutting.

  As in the first embodiment, the pipe P whose end is threaded is laterally fed to a position facing the installation position of the screw cleaning device 30, and a cleaning process for cleaning the pipe end after threading is performed. Executed. Specifically, the screw cleaning device 30 moves forward in the tube axis direction toward the end of the tube P, and cleaning with an organic solvent is performed. The screw cleaning device 30 moves back to the original position after cleaning the end of the pipe P.

  Next, as shown in FIG. 5, the pipe P whose end has been cleaned is laterally fed to a position facing the installation position of the cleaning maintenance device 60, and a drying process for drying the cleaned pipe end is performed. The Specifically, first, the end of the pipe P is carried into the cleanliness maintenance device 60. Then, the pipe P is laterally fed in a state where the end portion of the pipe P is located in the cleanness maintenance device 60, and during this time, the end portion of the pipe P is dried by the clean air in the cleanness maintenance device 60.

FIG. 6 is a schematic diagram schematically showing an example of the cleanliness maintenance device 60 that can be used in the present embodiment. 6A shows a perspective view, and FIG. 6B shows a side sectional view.
The clean maintenance device 60 of the present embodiment is an application of the technical idea of “clean space forming device” described in Japanese Patent Application Laid-Open No. 2003-248158 proposed by the present applicant.
Specifically, as shown in FIG. 6, the cleaning maintenance device 60 of the present embodiment includes a mesh filter (for example, a first chamber 61, a second chamber 62, and a first chamber 61 and a second chamber 62). The mesh size is 5 μm or less) 63. The wall surface of the second chamber 62 on the side into which the pipe P is carried is open. In addition, a part of the wall surface of the second chamber 62 on the side facing the measurement chamber 51 in which the automatic screw element measuring device 50 is installed (the place where the pipe P is carried into the measurement chamber 51) is also opened. It communicates with the chamber 51.

Clean air in a positive pressure state is supplied into the first chamber 61 of the clean maintenance device 60 from an air supply source 64 including an air filter and a pressurizing device via a pipe 65. The clean air supplied into the first chamber 61 removes particles according to the size of the mesh in the process of passing through the mesh filter 63 and is supplied into the second chamber 62. The clean air supplied into the second chamber 62 flows out through the opening of the second chamber 62.
With the cleaning maintenance device 60 having the above-described configuration, the end of the pipe P can be dried at the same time that the end of the pipe P is placed in a clean atmosphere in the course of the lateral feed of the pipe P.

  Finally, the end portion of the pipe P is carried into the measurement chamber 51 filled with clean air in a positive pressure state, and the screw element is measured by the automatic screw element measuring device 50 installed in the measurement chamber 51. After the measurement of the screw element, the pipe P is carried out into the second chamber 62 through the openings of the measurement chamber 51 and the second chamber 62, and further into the second chamber through the opening of the second chamber 62. After being carried out of 62, it is laterally fed.

  According to the thread element measuring method of the pipe end part according to the present embodiment described above, the end part of the pipe P is placed in a clean atmosphere between the drying process and the measurement process. For this reason, in the method according to the present embodiment, in addition to the advantages of the method according to the first embodiment described above, particles existing in the atmosphere of the screw machining line 100A adhere to the pipe end and the measurement accuracy of the screw element Therefore, the thread element can be measured with higher accuracy.

  In addition, although this embodiment demonstrated the aspect which dries a pipe end part with the clean air in the washing | cleaning maintenance apparatus 60, this invention is not limited to such an aspect. For example, the screw drying device 40 described in the first embodiment may be installed in the cleanness maintenance device 60, and the tube end portion may be dried by the drying device 40.

  Moreover, although this embodiment demonstrated the aspect in which the edge part of the pipe | tube P was put in a clean atmosphere between a drying process and a measurement process, this invention is not limited to such an aspect. For example, it is possible to adopt a mode in which the end portion of the pipe P is placed in a clean atmosphere between the cleaning process and the measurement process using a cleaning maintenance device 60A as shown in FIG.

More specifically, in the cleaning maintenance device 60A shown in FIG. 7, the screw cleaning device 30 and the screw drying device 40 described in the first embodiment are installed in the second chamber 62. Further, a space in the second chamber 62 (screw cleaning space) in which the cleaning process is performed using the screw cleaning device 30 and a space (screw drying in the second chamber 62 in which the drying process is performed using the screw drying device 40). Space) is partitioned by an openable / closable shutter 66A. Further, the screw drying space and the other space in the second chamber 62 are partitioned by an openable / closable shutter 66B. Clean air is supplied to the screw cleaning space via the pipe 65D, clean air is supplied to the screw drying space via the pipe 65C, and pipes 65A and 65B are supplied to the other spaces in the second chamber 62. Clean air is supplied via
The other configuration of the cleanness maintenance device 60A is the same as that of the cleanness maintenance device 60 described above.

  When the cleaning process is executed by the cleaning maintenance device 60A having the above configuration, the end portion of the pipe P is carried into the screw cleaning space, and the screw cleaning device 30 faces the end portion of the pipe P in the second chamber. Advancing through 62, cleaning with an organic solvent is performed. When this cleaning process is executed, the shutter 66A is closed, and scattering of the organic solvent S or the like to the adjacent screw drying space is prevented. The screw cleaning device 30 moves back to the original position after cleaning the end of the pipe P. Next, the shutter 66A is opened, and the pipe P is laterally fed to the screw drying space in a state where the pipe end portion is located in the second chamber 62.

When the drying process is executed, the screw drying device 40 moves forward in the second chamber 62 toward the end of the pipe P, and drying by air is performed. When this drying process is executed, the shutter 66B is closed, and scattering of the organic solvent S or the like to the adjacent space is prevented. The screw drying device 40 moves back to the original position after drying the end of the tube P. Next, the shutter 66B is opened, and the pipe P is laterally fed to the adjacent space in a state where the pipe end portion is located in the second chamber 62.
Subsequent operations are the same as in the case of using the above-described cleaning maintenance device 60, and thus the description thereof is omitted.

  According to the method using the cleaning maintenance device 60A described above, the end of the pipe P is placed in a clean atmosphere between the cleaning process and the measurement process, and therefore exists in the atmosphere of the screw processing line 100A. It can be expected that the possibility of particles adhering to the tube end and causing deterioration in the measurement accuracy of the screw element is further reduced.

  In the method using the cleaning maintenance device 60 </ b> A described above, the mode of drying the tube end using the screw drying device 40 has been described. However, as in the case of the cleaning maintenance device 60, the screw drying device 40 is used. It is also possible to use a mode in which the pipe end is dried with clean air in the cleanness maintenance device 60A without being installed.

<Third Embodiment>
In the first embodiment and the second embodiment described above, a drying step of drying the end portion of the cleaned pipe P is included. However, the present embodiment is different from the first embodiment and the second embodiment in that the drying process is unnecessary because granular dry ice is ejected together with compressed air in the cleaning process to clean the tube end.

FIG. 8 is a schematic view schematically showing an example of a screw cleaning device for carrying out the pipe element screw element measuring method according to the third embodiment of the present invention. 8A is a front view, FIG. 8B is a plan view, and FIG. 8C is an enlarged sectional view parallel to the tube axis direction of the tube end. As shown in FIG. 8, the screw cleaning device 30 </ b> A of the present embodiment includes a nozzle 34 positioned above the pipe P. The nozzle 34 advances in the axial direction of the tube P toward the end of the tube P until the nozzle 34 is positioned above the end of the tube P that has been threaded. After the forward movement is finished, granular dry ice D and compressed air are supplied from a supply source (not shown) to the nozzle 34, and the granular dry ice D is directed from the nozzle 34 toward the end of the pipe P. Are ejected together with compressed air. The dry ice D ejected from the nozzle 34 is dispersed in a linear shape along the axial direction of the pipe P. At this time, the pipe P is rotated in the circumferential direction by the turning roller R. Further, the nozzle 34 is moved in the axial direction of the pipe P as necessary. Through the above operation, the entire circumference of the end of the pipe P is cleaned, and the lubricant remaining on the pipe end during thread cutting and burr removal and the cutting waste adhering to the pipe end due to burr removal are removed. Can be expected.
The inventors set the ejection angle of dry ice D (angle θ shown in FIG. 8A) to about 45 ° with respect to the vertical direction (direction V shown in FIG. Distance is about 50 mm, cleaning width (width of dry ice D sprayed linearly) is about 40 mm, cleaning length (length of dry ice D sprayed linearly) is about 200 mm, and jet pressure is about 0 Washing was performed by rotating the pipe P once under the condition of 35 MPa and the rotational speed of the pipe P being about 10 rpm. Due to the lubricant remaining at the end of the pipe during thread cutting or burr removal, or burr removal. It was confirmed that the cutting waste adhering to the pipe end was sufficiently removed.

  Here, it is preferable to set the rotation speed of the pipe P when cleaning the pipe end to about 5 to 23 rpm. This is because if the rotational speed is less than 5 rpm, the dry ice D is excessively sprayed on the same portion of the end of the pipe P, and condensation is likely to occur (the drying process is unnecessary in this embodiment). This is because the advantage is lost. On the other hand, if the rotational speed exceeds 23 rpm, the lubricant remaining at the end of the pipe P during thread cutting or burr removal or the cutting waste adhering to the end of the pipe P due to burr removal may not be sufficiently cleaned. Because there is.

  In order to prevent the occurrence of condensation due to cleaning, it is preferable to set an upper limit on the number of rotations of the pipe P during cleaning. This is because if the number of rotations is excessively large, the dry ice D will be excessively sprayed on the same portion of the end of the pipe P. This upper limit value changes according to the rotation speed of the pipe P, and is preferably 1 rotation or less when the rotation speed is 5 rpm and 5 rotations or less when the rotation speed is 23 rpm. According to the above-mentioned conditions (the ejection angle θ: about 45 °, the distance between the nozzle 34 and the pipe P: about 50 mm, the washing width: about 40 mm, the washing length: about 200 mm, the ejection pressure: about 0.35 MPa. When the tube P was washed at a rotation speed of about 10 rpm, it was confirmed that condensation was generated when the tube P was rotated 3 times (no condensation was generated at 2 rotations or less).

Further, in order to effectively clean the flank surface of the threaded portion processed at the end of the pipe P, it is preferable to incline the nozzle 34 according to the inclination angle of the flank surface.
When the pipe P is an oil well pipe or the like, as shown in FIG. 8C, both the flank surfaces F1 and F2 positioned between the thread and the thread groove are changed from the thread to the thread groove. In many cases, it is inclined toward the tube end as it goes. In other words, of the flank surfaces F1 and F2, the flank surface F2 on the tube end side is inclined so as to be separated from the thread as it goes from the thread to the thread groove, while the flank surface F1 on the tube center side is In many cases, it is inclined so as to approach the center of the thread as it goes from the thread to the groove. When the inclination angle of the flank surface F1 (inclination angle with respect to the direction N perpendicular to the screw axis) is β and the inclination angle of the flank surface F2 (inclination angle with respect to the direction N perpendicular to the screw axis) is γ, β <γ. In many cases.
At this time, an inclination angle of the nozzle 34 with respect to the screw axis direction (tube axis direction) (an angle formed by an ejection direction (center C of the ejection direction) of the dry ice D from the nozzle 34 with respect to a direction N perpendicular to the screw axis). It is preferable to set α so as to satisfy the condition of β <α <γ so that both flank surfaces F1 and F2 can be cleaned. For example, when β = 3 ° and γ = 10 °, it is preferable to set the inclination angle α of the nozzle 34 so that 3 ° <α <10 °. Further, since the values of β and γ can take various values depending on the use of the pipe P, the value of the inclination angle α of the nozzle 34 is preferably not fixed but variable. That is, it is preferable that the nozzle 34 is installed so as to be tiltable with respect to the screw axis direction (tube axis direction) of the pipe P.

  As described above, in the present embodiment, the granular dry ice D is jetted together with the compressed air in the cleaning process to clean the tube end portion, so that the drying process is not necessary. Although different from the embodiment, for the other configurations, the same configurations as those of the first embodiment and the second embodiment can be applied as appropriate, and thus the description thereof is omitted here.

DESCRIPTION OF SYMBOLS 10 ... Lathe for screw cutting 20 ... Deburring device 30 ... Screw cleaning device 40 ... Screw drying device 50 ... Automatic screw element measuring device 100 ... Screw processing line P ... Pipe

Claims (5)

A method of automatically measuring screw elements at the end of a pipe after threading on a threading line in which the end of the pipe being sequentially conveyed is threaded,
A cleaning process for cleaning the pipe end after threading;
A drying step of drying the washed tube end;
Measuring the thread element of the tube end after the drying,
At least in the measurement step, the tube end portion is placed in a measurement chamber filled with clean air in a positive pressure state . A method of automatically measuring screw elements at the end of a pipe after threading on a threading line in which the end of the pipe being sequentially conveyed is threaded,
A cleaning process for cleaning the pipe end after threading;
A drying step of drying the washed tube end;
Measuring the thread element of the tube end after the drying,
During the period from at least the drying step to said measuring step, the screw element measuring method tube end you characterized in that the pipe end portion after the threading is placed under a clean atmosphere. A method of automatically measuring screw elements at the end of a pipe after threading on a threading line in which the end of the pipe being sequentially conveyed is threaded,
A cleaning step of spraying granular dry ice together with compressed air to the tube end after threading to clean the tube end;
Measuring the thread element of the pipe end after the cleaning,
At least in the measurement step, the tube end portion is placed in a measurement chamber filled with clean air in a positive pressure state .   4. The tube end portion according to claim 3, wherein in the cleaning step, the dry ice is sprayed linearly along the axial direction of the tube while rotating the tube at a rotation speed of 5 rpm to 23 rpm. Screw element measurement method.   The flank surface of the threaded portion of the tube has a shape that is inclined toward the tube end side from the thread to the thread groove,
The angle formed by the center of the jet direction of the dry ice with respect to the direction perpendicular to the screw axis direction of the tube is α, the angle formed by the flank surface on the tube center side from the thread is β, and from the thread 5. The method according to claim 3, wherein when the angle formed by the flank surface on the tube end side is γ, the spraying direction of the dry ice satisfies the condition of β <α <γ in the cleaning step. Method for measuring thread elements at the end of a pipe.